Orthopedic compression plate and method of surgery

ABSTRACT

An orthopedic plate has a first end including a locking screw hole that receives a locking screw and spaced from that hole is a closed compression housing that extends from the bone-facing side of the plate and which receives a compression screw that forms an angle of from about 10° to about 70° with a longitudinal axis of the plate. The compression housing is not located on the medial line of the plate, but is peripheral to the medial line, either in the longitudinal or the medial direction of the plate.

CROSS REFERENCE

This application is divisional application of pending U.S. patent Ser.No. 13/728,532, filed Dec. 27, 2012 for ORTHOPEDIC COMPRESSION PLATE ANDMETHOD OF SURGERY which is a CIP of U.S. Pat. No. 9,005,255, issued Apr.14, 2015 which claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Application Ser. No. 61/580,680, filed on Dec. 28,2011, herein fully incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to an orthopedic plate, which isconfigured to increase compression at a bone interface, in particular tostabilize bones or bone fragments relative to each other such as tocause fusion. Specific embodiments and methods of fixation are presentedfor fixation of the bones of the foot including, for example,stabilization of a fracture, dislocation or reconstruction of adeformity such as use in osteotomies and bunionectomies. The inventionalso applies to fusion procedures in other areas of the body, includingthe wrist or hand. The plate has a compression structure locatedgenerally peripherally to the mass of the plate, which receives a screwthat acts as an inter-fragmentary screw while the plate augments thestabilization and compression that is achieved by the screw. The plateis provided with an elongated structure or body that allows the plate tobe fixed to the bone fragments while the compression is achieved usingthe screw. In a further embodiment, the invention relates to a system ofplates for use in lapidus procedures and to a method of correction ofbunions using the present invention.

BACKGROUND OF THE INVENTION

The feet and the hands both include numerous bones and joints thatcooperate together to define quintessential human movement. They aresophisticated, delicate and altogether elegant in function and design.Together the foot and ankle have over 25 bones and 33 joints along withmore than 100 named muscles, tendons, and ligaments and a network ofblood vessels, nerves, all residing beneath a relatively slim coveringof soft tissue and skin. Structurally, the foot has three mainanatomical regions: the forefoot, the midfoot, and the hindfoot. Theseparts work together with the ankle, to provide the body with support,balance, and mobility. A structural flaw or malfunction in any one partcan result in the development of problems, which are manifested in otherareas of the body. The hand forms a cognate to the foot with 27 boneswithin the hand and wrist. There are eight small bones within the wristcalled the carpals, which join with the radius and the ulna to form thewrist joint. The carpals connect with the five metacarpals to form thepalm of the hand, which terminate in the rays (i.e., the thumb andfingers) formed by the phalanges. The three phalanges in each finger areseparated by two joints, called interphalangeal joints (IP joints). Theone closest to the MCP joint (knuckle) is called the proximal IP joint(PIP joint). The joint near the end of the finger is called the distalIP joint (DIP joint). The thumb only has one IP joint between the twothumb phalanges. The IP joints of the digits also work like hinges whenyou bend and straighten your fingers and thumb.

Similarly, the forefoot includes the five toes (which are also known asthe “phalanges”) and their connecting long bones (or “metatarsals”).Several small bones together comprise a phalanx or toe. Four of the fivetoes have three phalanx bones respectively connected by two joints. Thebig toe (or “hallux”) has two phalanx bones distal and proximal with ajoint in between called the interphalangeal joint. The big toearticulates with the head of the first metatarsal at the firstmetatarsophalangeal joint (the “MTP” joint) and there are two tiny,round bones called sesamoids on the plantar side of the metatarsal head.The phalanges are connected to the metatarsals at the ball of the foot.The forefoot balances pressure on the ball of the foot and bears asubstantial amount of the body weight. The first metatarsal forms ajoint at the mid-foot with the cuneiform. This joint is referred to asthe MTC joint or metatarsocuneiform joint. In the native position, thefirst metarsal is relatively parallel to the second metatarsal. Whenbunions are formed, the first metatarsal becomes displaced at an anglerelative to the second metatarsal, and often in response, the big toesubluxates.

The bones of the midfoot from medial to lateral are the 1^(st) through3^(rd) cuneiform, the cuboid, and the crescent shaped navicular boneposterior to the cuneiforms, which also forms a joint with the talusthat forms the basis for the ankle joint at the hinged intersection ofthe tibia, the fibula, and the foot. The five tarsal bones of themidfoot act together form a lateral arch and a longitudinal arch, whichhelp to absorb shock. The plantar fascia (arch ligament) underlays thebones of the midfoot and along with muscles, forms a connection betweenthe forefoot and the hindfoot. The toes and their associated midfootbones form the first through fifth rays beginning with the great toe asthe first ray. The bones which form the palmate portion of the hand are:the scaphoid, the lunate, the triquetrum, the pisiform, the trapezium,the trapezoid, the capitate, and the hamate, which act in concert toallow the opposition of the thumb with each of the fingers and to permitthe uniquely human ability to manipulate objects.

The hindfoot is composed of three joints (subtalar, calcaneocuboid &talonavicular) and links the midfoot to the ankle. The heel bone (or“calcaneus”) projects posteriorly to the talus and forms a lever arm toactivate the hinged action of the foot so as to allow propulsion of theentire body from this joint. The calcaneus is joined to the talus at thesubtalar joint. The mid-foot is often the subject of trauma, such asresults from falls, vehicle crashes and dropped objects. These accidentsoften result in severe fractures and/or dislocations. In addition, thereare several conditions which result from congenital deformation or whicharise as a result of repeated use type injuries. Surgical interventionthat includes surgical sectioning of bone or an “osteotomy” is oftenused to restructure the bones as a treatment for such conditions, forexample, the bunionectomy. The present invention is likewise useful forconditions of the hand that result from prior trauma, surgicalintervention or defects from birth or that develop with age (such asrheumatoid arthritis).

Examples of some of the other procedures with which the presentinvention could be used include hallus valgus and hallus rigiduscorrections, as well as lapidus surgeries. Other applications, whichcould use the present invention, include first and fifth metatarsalchevrons, translational osteotomies, closing wedge osteotomies,pediatric femoral osteotomies, metacarpal and calcaneal rotationalosteotomies, intrarticular osteotomies and hand and wrist realignmentosteotomies. Specific surgical techniques are discussed for the use ofan embodiment of the invention designed for use in bunionectomiesspecifically involving the MTP and MTC joints.

Typical surgical treatment of the foot or hand re-establishes a normalanatomy while the fractured bones mend. In some cases, fusion of a jointmay be necessary, for example, where arthritis arises in a patient dueto use injuries, poor bone or prior unsuccessful surgeries. One currentsurgical treatment of these conditions requires that pins, wires and/orscrews be inserted to stabilize the bones and joints and hold them inplace until healing is complete. For example, a pin or interfragmentaryscrew may be introduced medially into the internal cuneiform and throughthe base of the first and/or second metatarsal bone. While the use ofk-wires, pins, and screws may provide acceptable results for younger andmore plastic patients, these methods of fixation are not alwayssatisfactory, in particular in cases of early weight-bearing on theoperative joint, which can result in secondary issues such as elevatedmetatarsal, plastic deformation, or lesser metatarsal overload.

The present invention combines the advantages of the prior art screw/pinfusion methods with the advantages of a plate, and allows the surgeonthe option of using an inter-fragmentary or fusion compression screw ina procedure that also incorporates a plate and thus provides theadvantages for stress shielding and force loading or balancing thatpermits earlier weight bearing. Templates are provided which facilitatethe operative procedure, including alignment holes for the positioningof guide wires which can remain in position during placement of theplate, counter-boring the surgical site to accommodate the compressionscrew housing and placement of the “inter-fragmentary” or compressionscrew. Further, the plate includes elongated wire and/or screw holesthat allow for the compression and attendant relative bone movementduring the surgery by the engagement of the compression screw. Thecompression screw or screws are placed in the plate so as to minimizethe possibility of interference with the guide wires and plate screws.The openings in the plate for the compression screws are provided in aperipheral, and/or distal portion of the plate, and further for someapplications are displaced from and do not lie on the long axis of theplate body, but are offset from by means of a longitudinal curve in aextended or tail portion of the plate which receives the screw or byproviding a peripheral tab that curves inward so as to wrap the axis.This allows a placement of the compression screw that exerts a force ona diagonal to the long axis of the plate (i.e. a compound force relativeto the plate). Further, in one embodiment, a compression housing or“pocket” is provided which projects below the bone-facing surface of theplate, which includes a slotted opening for the compression screw. Thus,the screw can be angled with a single degree of freedom (i.e. linearly)with respect to the axis of the compression screw hole in the housing.

Finally, in a plate system in accordance with the present invention, asurgical tray is provided with a series of plates that include a varyingdegree of offset to accommodate the correction for a varying degree ofanatomical deformity in a lapidus procedure. Preferably this systemprovides for a left and right set of plates, each set optionallyincluding a first plate that has a compression slot rather than ashrouded compression housing, a “neutral” plate having a compressionhousing and a 3.5° offset between the posterior and anterior end of theplate, a 4° plate that has a total offset of 7.5°, a 8° plate that has atotal offset of 11.5° (all angles being expressed at +/−0.5°) and amedial column plate that is designed to provide for additional fixationof the first ray. At a minimum, the sets include the first plate whichis considered “neutral” (and has an offset of 2.5°-4.5°), the secondplate which has an additional offset of 2° to 5° (for a total of4.5°-9.5°) and a third plate has an additional offset of 6° to 10° (fora total of 10° to 20°). The system provides for at least these threeplates available during a surgery in a single tray, and additionally thesystem provides for a left set and a right set of implants, for a totalof at least six plates available to the operating surgeon. Optionally,the system may also include a non-pocket plate that has a double tabbedend and an opposing tri-lobed end with the intermediate lobe including acompression slot, and the system may include a medial column plate thathas a series of threaded medial tabs for locking screws and at one end alobe that has a terminal compression slots to achieve compression towardthe other end of the plate, and the other end of the plate has a middlecompression slot which acts to achieve compression towards the middle ofthe plate.

SUMMARY OF THE INVENTION

In accordance with the present invention an orthopedic plate is providedthat achieves improved compression through the use of a screw that issituated with its axis obliquely to the spine of the plate (i.e. to thelongitudinal axis in the plane of the plate taken at the opening of thecompression opening of the plate). The term “spine” of the plate is usedto mean a line or curve that is generally medial to the mass of theplate, taking into account that the plates of the invention are somewhatmore long than wide, but are amorphous in profile, and have end sectionsthat are may be asymmetrically lobed or tabbed with semi-circularconjoined tabs including screw holes that can have internal threads forlocking screws.

Preferably, the compression screw is received in a housing or pocketwhich includes an opening in the top surface of the plate and a shroudwhich extends from the bottom surface of the plate so as to define apocket on the bottom of the plate that captures the screw at a variableorientation. The housing extends through the plate to accommodate theentire diameter of the head of the screw (i.e. so that the head of thescrew does not project significantly or at all beyond the top of theplate when the screw is fully implanted within the plate). Thus, thescrew head does not project beyond the top surface of the plate when thescrew is fully seated in the housing. (By “top” it is meant herein theexterior facing surface, which is opposite through the thickness of theplate from the bone-facing surface, of the plate when the plate is inposition on the bone. It is understood that the orientation relative tothe ground is dependent on the orientation of the plate in space, andtherefore that is not relevant in determining what is “top” in thiscase). The housing also includes an opening on the bottom of the platethrough which the screw extends and which is smaller than the diameterof the screw head so as to capture the screw in the housing. Also thehousing is slightly larger than the bottom opening so that the convexlyrounded screw head has some play in the pocket to allow some freedom ofangulation (i.e. about 5 to about 30°, preferably about 10 to about 20°)of conical or modified conical rotational freedom of the screw relativeto the housing axis (as measured from the groove formed through thecompression opening.) In a further embodiment, the opening is elongatedor is a slot, which allows the screw to be placed at a linear variableangle (that is a restricted portion of the conical angulation) relativeto the housing, where the amount of angulation is about +/−12°,preferably +/−10°, and more preferably +1-6° of linear freedom relativeto the axis of the housing. The angle of the axis of the oblique screwis from about 10° to about 70°, more specifically about 25° to about 60°and most specifically about 35° to about 55° degrees to a longitudinalaxis of the plate which dissects the compression opening on the plate(i.e. the “spine of the plate”). A compressive force is applied to thebone or bone fragments by the plate as the oblique screw is screwedtighter and the screw head compresses into an increased fit with thepocket, and in particular with the pocket bottom opening. This drawsthat bone segment into which the compression screw is screwed, towardthe locking screw or screw in the other end of the plate and accordinglyinto compression with the bone segment into which the screws associatedwith the other end of the plate, are screwed.

In a first embodiment, of the plate, an application specificconfiguration is illustrated as a MTP plate, which is intended to spanthe MTP joint. In a first version of the MTP plate of the presentinvention, the plate outline has (again “consists essentially of”) afirst end with two lateral tabs on either side of a middle tab, and asecond end with two lateral tabs and no intermediate tab. Each of thesetabs is provided with a threaded screw hole that receives a threadedlocking screw. The end with the two tabs, also includes a compressionhousing as previously described that accepts a screw which extendstoward the first end of the plate with its axis at an oblique angle ofabout 5° to about 40°, more preferably about 10° to about 30°, and mostpreferably about 15° to about 25° with respect to the longitudinal axisof the plate. Further, the plate has an angle of up to about 10° (andpreferably about 5°) for dorsiflexion and an angle up to about 10° forvalgus. The bottom surface of the plate is radiused. This allows theplate to be in snug contact with the bone. This plate is also providedin a second version which differs from the first in that the second enddoes include three tabs similar to the first end, an the compressionhousing is located at at an oblique angle of about 5° to about 40°, morepreferably about 10° to about 30°, and most preferably about 15° toabout 25° to the lateral side of the plate and intermediate along thelongitudinal axis to the tabs, and further houses a screw hole thatdefines an axis at an angle of about 55°, /− about 15°, preferably about10°, and most preferably about 5° to a line perpendicular to the platesurface at a point along the plate longitudinal axis. The compressionhousing is similar in concept to the previously described compressionhousing, but in this case, has a round footprint describing at least aportion of a circle, and preferably is substantially a portion of acircle, with a leading edge that is linear. Once again, the housing hasan internal recess that houses the compression screw and which has anarrowed opening, that is smaller than an associated screw head so as tocapture and retain the screw, but which allow for conical rotation inthe compression housing.

A third embodiment of the plate is intended for use in lapidusprocedures which are also used to correct bunions, but by realigning themetatarsal relative to the rear joint with the cuneiform. Lapidusprocedures in accordance with the present invention have severaladvantages over past procedures, including earlier post operative weightbearing, inhibition of elastic deformation, preservation of the functionof the MTP joint, realignment of the big toe, better outcomes in theevent of mal-union or non-union, and better rear-foot alignment.

In the plate system in accordance with this embodiment, the plate has aneven more complex footprint with the posterior end (i.e. toward the heelend of the plate) of the plate including a double tabbed end with eachtab including a threaded locking screw hole, and where the inferior tabproceeds (i.e, is rearwards of) the superior tab in the posteriordirection. The anterior end of the plate includes a tri-lobed outline inwhich the central lobe and the superior lobe or tab include internallythreaded locking screw holes, and the third lobe or tab which is lessdistinct than the other two lobes and is curved inward and downwardtoward the bone-facing surface. This lobe includes a shroud, housing orpocket which projects below the plate as the previously described screwhousings, and which receives a screw that projects posteriorly anddorsally to apply compression across the MTC (metatarsocuneiform) joint.This embodiment of the invention differs from the first embodiment inthat the compression screw housing is provided in a location that doesnot lie on the longitudinal axis, and more preferably is located in aperipheral (both longitudinally and medially) portion of the plate whichaccepts a screw so as to pull a compressive force diagonally across thebody of the plate in opposition to the plate screws that hole the platein position relative to the bone segments. Thus, the screw applies acompound force (i.e. having force components in the direction of thelongitudinal axis and transverse to it) so that this plate presents theadvantages of the prior art interfragmentary screws which tend to beplaced in this position, combined with the additional stability andweight bearing ability of a plate which wraps the bone and creates aconstruct with the bone that is aligned to stabilize with the bone axes.

The invention also relates to a novel surgical procedure, which is abunionectomy that involves the use of the bunionectomy plate of thepresent invention, as well as to a lapidus procedure which utilizes theplate in accordance with the invention where a template is placed alongwith guide wires, the bone is reamed to receive the compression screwpocket, the template is slid off the guide wires and the plate is slidon, all the time maintaining the established alignment of the bones withthe guide wires. The distal plate screws are place in the anterior endof the plate, a guide wire is placed through the joint, and a cannulatedscrew is placed in the compression pocket across the joint. Since theplate is provided with slot or slots in opposition to the compressionpocket, and the template is provided with guide wire holes spacedappropriately to account for the compression achieved with the screw,the guide wires move in the slots in the plate to account for thecompression achieved by the compression screw. The guide wires can beremoved, the posterior screws are implanted, and the wound can beclosed. The plate and template system allow the security of the guidewire used for the interfragmentary compression, and the screws allow formultiplanar fixation, while inhibiting the possibility of screwinterference. Alternatively to the guide wire slots, the plate caninclude slotted screw holes and the plate can be attached to bone usingthese slotted holes prior to the tightening of the compression screwwhere the screws slide in the slot to account for a change in therelative position in the plate as compression is achieved across thejoint or between the bone fragments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a first embodiment of the orthopediccompression plate in accordance with the present invention;

FIG. 2 is a top view of the orthopedic plate of FIG. 1;

FIG. 3 is a bottom view of the orthopedic plate of FIG. 1;

FIG. 4 is a side and bottom perspective view of the plate of FIG. 1,

FIG. 5 is a first side view of the plate shown in FIG. 1;

FIG. 6 is a first cross-sectional view of the plate shown in FIG. 2,taken along line 6-6;

FIG. 7 is a side view taken from the other side of the plate shown inFIG. 1;

FIG. 8 is a second cross-sectional view of the plate shown in FIG. 2,taken along line 6-6 and looking in the opposite direction from FIG. 6;

FIG. 9 is a left end view of the plate shown in FIG. 1;

FIG. 10 is a right end view of the plate shown in FIG. 1;

FIG. 11 is a top view of a second version of the embodiment of the plateshown in FIG. 1;

FIG. 12 is a first side view of the plate shown in FIG. 11;

FIG. 13 is a cross-section of the plate shown in FIG. 11 taken alongline 13-13;

FIG. 14 is a bottom view of the plate shown in FIG. 11;

FIG. 15 is a cross-section of the plate shown in FIG. 11 taken at line15-15;

FIG. 16 is a top view of a left version of the embodiment of the plateshown in FIG. 11;

FIG. 17 is a detail in cross section of the plate shown in FIG. 11;

FIG. 18 is a top view of a third embodiment of the orthopediccompression plate in accordance with the present invention;

FIG. 19 is a first side view of the orthopedic plate of FIG. 18;

FIG. 20 is a bottom view of the orthopedic plate of FIG. 18;

FIG. 21 is a first end view of the plate of FIG. 18;

FIG. 22 is a second end view of the plate shown in FIG. 18;

FIG. 23 is an end and bottom view of the plate of FIG. 18 whichillustrates the compression screw opening;

FIG. 24 is a bottom view of the orthopedic plate of FIG. 18 includingassociated screws to form a plate assembly;

FIG. 25 is a first side view of the orthopedic plate assembly of FIG.24;

FIG. 26 is a top view of the orthopedic plate assembly of FIG. 24;

FIG. 27 is a first end view of the plate assembly of FIG. 24;

FIG. 28 is a second end view of the plate assembly shown in FIG. 24;

FIG. 29 is a view showing top and side views of a left and a right setof plates in accordance with a further embodiment of the invention;

FIG. 30 is a side view of a non-locking screw that can be used with theinvention;

FIG. 31 is a side view of a locking screw that can be used with theinvention;

FIG. 32 is a side view of a variable locking assembly that can be usedwith the invention;

FIG. 33(a)-33(l) illustrates a method of performing a surgery using theplates and instruments in accordance with the invention; and

FIG. 34 is an alternative embodiment of the MTC plate of FIG. 18.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-10 show a first version of plate for use in the MTP joint, thejunction of the head of the first metatarsal and the proximal phalangeof the first ray (i.e. the great toe) at the first metatarsophalangealjoint. The plate used in fixation (i.e. for fusion) of the bones of thefirst MTP joint, and is thus termed an MTP plate. The plate 110 has afirst end 112 which is tri-lobed, or has three rounds tabs 113, of justappropriate size to form mounting rings for threaded locking holes 114which receive the locking screws having an externally threaded lockinghead. The tabs include a rounded portion for example large enough toaccommodate an opening for a screw hole, and contiguous material thatholds the rounded projection to the general plate body. The tabs arelongitudinally offset from each other, and angled inward toward themedial axis of the plate to improve the purchase in the plate, andinhibit backout. The other end 118 of the plate 110 includes twolaterally and longitudinally offset tabs 115 which are also just ofappropriate size to form mounting rings for threaded locking holes 114which receive threaded locking screws 130. The second end 118 of theplate includes a compression housing similar 116.

The compression housing 116 includes an opening 120 in the top surface122 of the plate. The opening 120 is ovoid, with a width that wideenough to accept the compression screw 132 that is received in theopening 120. The compression screw is of slightly greater diameter andof greater length than the locking screws. The opening 120 angles intothe top surface 122 of the plate 110 so as to form a groove 124 thataccommodates and guides the screw 132 and a mating driver as the screwis screwed into the bone below the plate. On the bottom surface 123 ofthe plate 110 there is a shroud 126, which has a rectangular flat rearsurface 127 joined to flat side walls 128. The term “shroud” as usedherein means that the housing creates a “pocket” of enclosed space forthe compression screw head, which is closed to the bone surface and inwhich the structure that defines the enclosed space is connected at eachside to the bottom of the plate. This reinforces the housing structure,helps to create additional compression and closes the housing from thepossibility of tissue interference or in-growth. The “housing” comprisesa more complete structure than a flat solid rib which projects from thebottom surface of the plate and includes a screw hole (threaded or not).The shroud 126 includes a lower opening 129 which is circular, and whichis large enough to allow the major diameter of the screw to passthrough, but which is smaller than the diameter of the rounded portion134 of the head of the screw 132. The compression housing 126 accepts ascrew 132 which extends toward the first end 112 of the plate with itsaxis at an oblique angle of about 5° to about 40°, more preferably about10° to about 30°, and most preferably about 15° to about 25° withrespect to the longitudinal spine of the plate. Further, the plate hasan angle of up to about 10° (and preferably about 5°) for dorsiflexionand an angle up to about 10° for valgus. The bottom surface of the plateis radiused at a constant curve.

FIGS. 11-17 illustrate a second embodiment, i.e. the MPT plate 310, ofthe present invention. In this version both the first and the secondends 312,318 includes three tabs 313,315 and locking holes 314 withineach tab. The plate 310 continues to have the same angles fordorsiflexion and for valgus. In the first end, in which an axis can bedefined along the medial axis of the plate to the mid-line, and dividingthe terminal most screw hole in half, the second tab hole forms an angleof about 25° to the long axis and the screw hole has an angle of about21°+/−8°, preferably +/− about 5°, and most preferably about 2° to thescrew axis of the terminal most hole, while the screw hole in the thirdtab has an angle of about 18°+/−8°, preferably +/− about 5°, and mostpreferably about 2° to the screw axis of the terminal most hole, with apreferred difference of about 3°. The geometry of the opposite end ofthe plate mirrors the first end, with the exception that the second endfurther includes a tab 317 for a compression shroud 316 which extendsfrom the bottom surface of the plate and intermediate to the second taband has a screw housing that extends from the bottom of the plate at anangle of about 55°+/− about 10°, preferably about 8°, and mostpreferably about 5° relative to the screw hole axis of the terminal mostscrew hole. The housing has a cylindrical configuration, whichintersects the plate at a linear edge. The housing has a narrowedopening that acts to capture a screw housed in the housing but whichallows conical rotation in the housing. The inside wall of the housingnarrows at an angle of 40° relative to the axis of the housing. Thehousing 316 has a narrowed opening that acts to capture a screw housedin the housing but which allows conical rotation in the housing. Theinside wall of the housing narrows at an angle of 40° relative to theaxis of the housing. On the bottom surface 323 of the plate 310 there isa shroud 316, which has a rear surface 327 joined to side walls 328. Theshroud 316 includes a lower opening 329 which is circular, and which islarge enough to allow the major diameter of the screw to pass through,but which is smaller than the diameter of the rounded portion 234 of thehead of the screw 232. FIG. 16 shows right plate MPT plate 410 which isa mirror image of the left MPT plate shown in FIG. 10. Once again, boththe first and the second ends 412,418 includes three tabs and lockingholes 414 within each tab and the second end also includes a tab 417 fora compression shroud 416 which extends from the bottom surface of theplate. The plate continues to have the same angles for dorsiflexion andfor valgus. The geometry of the opposite end of the plate mirrors thefirst end, with the exception that the second end further includes afourth tab intermediate to the second tab and has a screw housing thatextends from the bottom of the plate at an angle of about 55°+/− about10°, preferably about 8°, and most preferably about 5° relative to thescrew hole axis of the terminal most screw hole. The housing has acylindrical configuration, which intersects the plate at a linear edge.

FIGS. 18-28 illustrate a third embodiment of the invention which is alapidus plate and assembly designed for use in lapidus procedures. Thisplate 510 has a first end 512 and a second end 518, where the first endincludes two tabs 515, each having internally threaded locking screwholes 514. A second end 518 has three conjoined tabs or lobes 515 two ofwhich include internally threaded locking screw holes 514. The thirdlobe includes a compression housing 516 that projects into the plate soas to provide a seat for a compression screw and a structure that willalso contribute to this compression in the bone. Once again, thiscompression housing is a peripheral compression housing that is notlocated on the spine or longitudinal axis of the plate, and the screwlocated in this housing does not act to apply a force substantiallysolely in the direction of the longitudinal axis or along the spine ofthe plate, but rather acts so as to apply a compound force that isdirected in a diagonal direction across the body of the plate. Theopening of the housing is elongated or slotted in the directiontransverse to the axis of the slot so as to define linear angulation inthe slot hole for the compression screw.

The plate also includes at least one slot 520 having a long axis, whichis aligned with the direction of compression imposed by the compressionscrew. The slot receives a guide wire and allows it to remain in placestabilizing the bone fragments as the compression screw is tightened anda first bone segment is compressed against a second bone fragment.Optionally, the plate may include an additional guide wire hole 524located in the vicinity of the compression housing. It is noted that theguide wire holes are smaller than the screw holes, and have a diameterthat is slightly (i.e. between about 3 and 10% larger in diameter than,and preferably greater than about 3 and 7% larger than the diameter of aguide wire where the slotted version is from 1.5 to 3 times the diameterin length.) Alternatively as shown in FIG. 34, the slotted guide wirehole could be a slotted screw hole or compression hole 521 with asimilar ratio of length to width (i.e. providing for a length thatcorresponds to the amount of compression that is achieved and is about1-5 millimeters.) FIGS. 24-28 illustrate the plate 510 including platescrews 526 and compression screw 528. These views illustrate how theinvention provides for the compression screw with a minimized concernfor interference with the plate screws. FIG. 30 illustrates a threadedlocking screw 600, that can be used with the invention, while FIG. 31illustrates a compression screw 610, and FIG. 32 illustrates a variablelocking screw assembly 620 that can be used with the present invention.

The lapidus plate also includes mid-section 530 located intermediate thefirst and second ends and which can provide for an offset of varyingdegrees. Thus, in the plate system shown in FIG. 29, the plates areshown with a varying degree of offset provided in the mid-section. Amedial column plate 511 is also provided which includes two opposingcompression slots that act in opposition to each other, and which areprovided in the distal and proximal ends of the plate. The systemincludes left and right versions of a non-pocketed plate 509; a neutralplate 510; a 4° correction plate 510(a); a 8° correction plate 510(b)and the medial column plate 511.

In one method of causing locking of the screw relative to the plate, thescrew 600 could include external screw threads 602 that mate withinternal threads in the locking screw hole at a pre-selected angle, insome instances, the screw axis is perpendicular to a tangent at the topof the screw hole so that the screw axis angles slightly toward thebottom of the plate. However, other methods of causing locking could beemployed, such as a variable locking assembly 622. The screw 610 used inthe compression housing has a rounded rear shoulder 612 (such as ahemisphere, or a torroid), which allows for play in the convexly roundedrecess in the compression housing. The compression is caused when thecompression screw engages the bone and pulls the plate into that bone asit engages a downwardly sloping shoulder on the compression slot, andthe locking screw or screws act on their respective bone segment.

The screws shown in FIGS. 30-32 which are useful with the plate of thepresent invention are self-starting, self-tapping screws including theoption of partial or full cannulation. The screws include a cutting endhaving multiple flutes, and preferably 2 or 3 flutes about a conicalrecess, and preferably have a rounded end to avoid soft tissueirritation should they break an opposing cortical surface. The screwsfurther include a partial taper of the inner diameter in the proximalend over the first several thread turns, for example over 2-8, andpreferably over 3-5 turns in order to increase the fatigue life of thescrew as well as providing potential physiological advantages in use.The screws further include a torque driving recess.

The plate is formed of a biocompatible material, and preferably a metalsuch as surgical grade stainless steel, titanium or a titanium alloy.Preferably, the plate has a thickness of between about 1.0 and 2.0millimeters, more preferably between about 1.2 and 1.5 millimeters, andmost preferably between about 1.25 and 1.40 millimeters. The compressionhousing extends a depth below the bottom surface of the plate from about1.4 to about 3 mm, preferably from about 175 to about 2.25 mm, and has awidth of from about 3.5 to about 5.5, preferably from about 4 to about 5mm, and a length of from about 3.0 to about 8.0, mm preferably fromabout 5.0 to about 7.0 mm. The opening in the upper surface of the platefor the compression opening is from about 8 to about 15 mm in width, andfrom about 10 to about 18 mm in length. The lower opening is about 2.5to about 2.9 mm in diameter with a recess width of from about 2.5 toabout 4.5 mm. The locking screw holes include a flat annular recesssurrounding the threaded area that is about 0.4 to about 0.6 mm inwidth. The universal plate (i.e. the tab-like plate) has a length offrom about 35 to about 45 mm, preferably from about 38 to about 42 mm,and the compression screw axis forms an angle of from about 30° to about40° to a longitudinal axis on the top of the plate. The MTP plate has alength of from about 40 to about 50 mm in length. The compression screwaxis forms an angle of about 22° to about 37° with a longitudinal axistangent to the bottom of the plate at the housing exit. In thebunionectomy plate, the chamfer at the bone insertion end is from about5° to about 15°, preferably from about 8° to about 12°, and the lengthof the chamfer is from about 2 to about 4 mm, preferably from about 2.5to about 3.5 mm and the plate has a total length of from about 175 toabout 225 mm, preferably from about 185 to about 200 mm, with the taper.The axis of the compression screw forms an angle of from about 35° toabout 45° to a longitudinal axis on the bottom of the plate. The plateincludes a continuous outer edge, which is defined between the top andthe bottom surface. In addition, the plate can include a small throughhole sized to receive a K-wire or other similar guide wire.

During the surgery the joints are first prepped which may includede-articulation between the bones to be fused. The bones are reduced,the plate is located such that all of the screws are aimed into thetargeted bones and away from the joint, and the locking screw(s) isinserted into a pre-drilled pilot hole or holes. A pilot hole is drilledfor the compression screw, and the compression screw is tightened intoposition. The two locking screws are screwed into adjacent cunieforms.The plate is viewed radiographically. The incision is closed per theusual method.

The following is a description of a surgical technique for an MTP fusionusing the MTP fusion plate in accordance with the present invention.First, prepare the MTP joint for fusion and choose the desired platefrom the surgical tray. Note, that the plates are pre-contoured toprovide 10° of valgus and 5° of dorsiflexion and can be used on eitherfoot. The plates should be placed so that the plate's pocket is on themedial side of the foot. For instance, using the Alpha™ plate on theright foot the pocket is on the proximal side of the joint. When used onthe left foot, the pocket of the Alpha™ plate is on the distal side ofthe joint. If necessary, use the bending pliers to contour the plate tothe bone surface. Using a k-wire, placed in the plantar portion of thebones from medial to lateral across the joint, temporarily fix the jointin the desired position. Assemble the template that corresponds to thechosen plate with the countersink guide by snapping the template intothe guide. Lay the template on the bone and orient to the desiredposition of the plate. Place two 0.9 mm k-wires. Prepare for the platepocket and inter-fragmentary screw with the provided countersink throughthe template assembly. Insert the countersink until the shoulder of thecountersink hits the guide normal to the plate in the k-wire holes. Withthe k-wires still in place, slide the template off the bone and usingthe wires to help placement, slide the chosen plate over the k-wires sothat the plate's pocket fits within the prepared hole. Select one of afixed locking, non-locking or variable angle locking screw to be used inone of the threaded locking holes that is on the same side of the joint,proximally or distally, as the pocket and chose the appropriate drillbit based on the screw selection. Using a color-coded drill guide, drillto the desired depth, determine the screw length using the depth gages,and insert a selected screw into the hole and drive the screw for eachscrew hole. Using the 1.4 mm guide wire tip, insert a 1.4 mm guide wirein to the pocket hole across the MTP joint and ensure that the guide tipis seated within the pocket before inserting the wire. Use thecannulated drill bit to drill for the inter-fragmentary pocket screwover the guide wire. Determine the required screw length over the guidewire using the depth gage and insert the inter-fragmentary screw in thepocket of the plate using the corresponding driver. Before the pocketscrew is completely seated, remove the k-wire used for temporaryfixation and fully tighten the pocket screw. Fill all remaining screwholes and completely tighten all remaining screws. Verify the correctplacement of the plate and screws, replace soft tissue and close theopening.

The present invention offers a site-specific design for fixation andfusions involving the first metatarsocuneiform (MTC) joint. The systemincludes several plates for varying degrees of deformity correction,from neutral (no correction) to 8° past neutral. All plates feature ananatomically contoured design to fit the medial aspect of the joint. Theimplant design allows the plate to fit the flatter cuneiform and curvedfirst metatarsal, creating a low-profile construct and reducing the needfor intra-operative plate bending. The present invention allowsinsertion of a targeted 4.0 mm inter-fragmentary screw through theplate, designed to maximize compression and reduce the risk of hardwarecollision associated with supplementary cross-screw insertion outside ofa plate. The system further allows the plates to accommodate all ofnon-locking, fixed-angle locking and variable-angle locking screws forfixation without compromise. The compression screw can be a partiallythreaded or fully threaded cannulated or solid screw. All of these canbe provided in the surgical tray or caddy and thus are made available atthe time of surgery.

The steps of the surgery are detailed below:

Step 1: Perform standard exposure and prepare the metatarsocuneiform(MTC) joint according to surgeon preferred technique for a medialapproach.

Step 2: Temporarily fix the joint in the desired orientation using theprovided k-wires. Recommended wire placement is through the dorsalaspect of the joint, directed into the plantar-lateral aspect of thecuneiform and into the intermediate cuneiform or second metatarsal ifdesired. FIG. 33(a).

Step 3: Select the plate template. The plate and templates are sidespecific and designed so that the pocket is on the plantar-medial aspectof the joint and a template is provided at each offset corresponding tothe appropriate degree of correction: i.e. neutral (0° of correction),4° past neutral, and 8° past neutral. Note that the neutral template hasa slight bend to fit the natural angle of the joint. The 4° and 8°designations reflect the amount of bend past neutral and do notnecessarily correspond to the total IM correction angle.

Step 4: Insert a 1.4 mm k-wire through each k-wire hole in the template.The templates include raised nubs which surround the guide wire holes inorder to provide for parallel placement of the guides wires relative toeach other, and an alignment that is desired relative to the foot. Takecare to keep the wires parallel during insertion as they will laterfacilitate plate placement. FIG. 33(b).

Step 5: Select the provided countersink and drill through the templateto prepare a pocket for the plate. FIG. 33 (c). Ensure that the templateis held tightly against the bone during this step in order to fullyprepare the pocket. Insert the countersink until the shoulder of thecountersink hits the guide. FIG. 33(d).

Step 6: With the k-wires still in place, slide the template off thebone. Then slide the corresponding plate over the wires and positioninto the prepared pocket. FIG. 33(e). The proximal k-wire should passthrough the k-wire slot in the plate.

Step 7: Using the fixed drill guide and the 2.4 mm drill bit, drill apilot hole for the most distal screw. FIG. 33(f). Take care to not movethe plate after drilling for a locking screw in order to maintain theproper pilot hole alignment and prevent locking screw cross-threading.The threaded screw holes in the plate are compatible with a variety ofscrew options; 3.5 mm non-locking or fixed-angle locking screws(magenta) and 4.0 mm non-locking screws (teal) are included in the Set.Depending on surgeon preference, a combination of screw types can beused.

Step 8: Determine the screw length required using the provided depthgage.

Step 9: Remove the desired screw from the screw caddy using the provideddriver. For all screws used throughout the procedure, verify the screwlength using the gauge provided on the screw caddy.

Step 10: With the driver, insert the selected screw into the hole anddrive the screw.

Step 11: Follow the same technique for the remaining distal screw hole.

Step 12: Select the 1.4 mm pocket wire guide and place the nose into theplate pocket, aligning the solid line on the guide with the dashed lineon the plate.

Step 13: With the guide fully seated in the plate pocket, insert a 1.4mm guide wire through the guide at the desired trajectory. FIG. 33(g).The recess within the pocket wire guide is slotted to allow for 12° ofplanar angulation within the slot of the compression housing. Verifywire placement with fluoroscopy to ensure trajectory and screw purchasewill be adequate.

Step 14: Remove the pocket wire guide and use the provided pocket depthgauge to measure over the wire and determine the required screw length.Keep in mind that a shorter screw may be required based on compressiongeneration. FIG. 33(h).

Step 15: Use the cannulated drill bit to drill over the wire for the 4.0mm pocket screw.

Step 16: Remove the 1.4 mm guide wire from the pocket in order to inserta partially threaded solid screw. Leave any other provisional fixationin place to maintain proper alignment. FIG. 33(i). If a cannulated screwis used the pocket guide wire may be left in place during initial screwinsertion to further maintain joint alignment.

Step 17: Using the driver, insert the appropriate length partiallythreaded screw through the pocket until almost fully seated in thepocket. FIG. 33(j).

Step 18: Remove any provisional fixation wires and fully tighten thepocket screw. The proximal k-wire may remain in place during screwinsertion to maintain plate alignment; the slot will allow platetranslation during pocket screw insertion.

Step 19: Remove all remaining wires. Drill and insert the proximalscrews using the technique described in Steps 8-10 above. Fully tightenall screws. FIG. 33(k). Verify final plate and screw placement withfluoroscopy to ensure correct joint. FIG. 33(l).

While in accordance with the patent statutes the best mode and preferredembodiment have been set forth, the scope of the invention is notlimited thereto, but rather by the scope of the attached claims.

1.-17. (canceled)
 18. A plate, comprising: a body having a thickness extending between a top surface and an opposing bone facing surface, the body extending along a longitudinal axis between a first end and a second end, wherein the body defines a medial line, wherein the first end includes a terminal portion defining at least one locking hole, wherein the body defines at least one guide wire slot sized and configured to receive a guide wire therethrough; and a compression screw housing located at a position spaced apart from the first end and not located on the medial line, the compression screw housing extending from the bone facing surface of the body, wherein the compression screw housing defines a compression screw hole extending at a compression screw angle relative to the longitudinal axis at an angle substantially between 10° to 70° from the top surface through the compression screw housing, wherein the compression screw hole defines a groove in the top surface of the plate, wherein the compression screw holes is configured to receive a compression screw therethrough, wherein the compression screw is configured to apply a compressive force to a first bone part when inserted through the compression screw hole, and wherein the guide wire slot has a length in the direction of the compression screw hole which is greater than a width of the guide wire slot.
 19. A system, comprising: at least one locking screw having a first diameter and a first length; a compression screw having a second diameter and a second length, wherein the second diameter is greater than the first diameter and the second length is greater than the first length; and a plate comprising having a top surface opposing a bone facing surface in a z direction, the plate extending along a first length along a longitudinal axis and having a body extending along the longitudinal axis and defining a first end and a second end, the body defining a medial line, the first end having a terminal portion with a locking hole and the plate including a compression screw housing extending from the bone facing surface of the plate and located at a position spaced apart from the first end and not located on the medial line and defining a compression screw hole extending at a compression screw angle relative to the longitudinal axis of about 5° to 40°, wherein the compression screw is configured to apply a compressive force to a first bone part when inserted through the compression screw hole.
 20. A plate and screw system capable of fixation of bone comprising: a plate, a locking screw, and a compression screw; the plate having a body extending defining a first end and a second end with a top surface configured to oppose a bone surface, a locking hole defined adjacent to the first end a compression screw housing located at a position spaced apart from the first end and defining an angled compression screw hole extending at an angle relative to top surface that is less than 90°, the compression screw housing projecting from top surface wherein the compression screw is configured to apply a compressive force to a first bone part when inserted through the compression screw hole.
 21. The plate and screw system as set forth in claim 37, wherein the compression screw angle is from about 10° to about 70°.
 22. The plate and screw system as set forth in claim 38, wherein the compression screw angle is from about 20° to about 60°.
 23. The plate and screw system as set forth in claim 37, wherein the compression screw housing is off-set in relation to an edge of the plate.
 24. The plate and screw system as set forth in claim 37, further including a plurality of locking screws, and wherein the first end of the plate defines a plurality of tabs, each tab including a threaded hole for a locking screw.
 25. The plate and a screw system as set forth in claim 37, wherein the first end and the second end are offset by angle between 2° and 14°.
 26. The plate and a screw system as set forth in claim 42, wherein the first end has three tabs with each defining a locking hole, and the second end defines two holes with each defining a locking hole, and the compression screw housing being located intermediate of the first end and the second end.
 27. The plate and a screw system as set forth in claim 43, wherein the first end has only two tabs with each defining a locking hole and the second end has three lobes with each defining a locking hole and the second end further includes a fourth lobe which defines a compression hole.
 28. The plate and screw system as set forth in claim 37, wherein the plate further defines a slot having a width sufficient to accommodate a guide wire, and a length greater than the width. 